Added MetadataService with GetHealth and GetVersion

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added `GetClients` to `SrsService`, which retrieves a list of units that are connected to SRS and the frequencies they are connected to.
 - Added `SrsConnectEvent` and `SrsDisconnectEvent` events 
 - Added `GetDrawArgumentValue` API for units, which returns the value for drawing. (useful for "hook down", "doors open" checks)
+- Added `MetadataService` with `GetHealth` and `GetVersion` for quick checks on health (even when DCS mission is unresponsive) and version.
 - Added Authentication Interceptor. This enables authentication on a per client basis.
 
 ### Fixed

protos/dcs/dcs.proto

@@ -9,6 +9,7 @@ import "dcs/controller/v0/controller.proto";
 import "dcs/custom/v0/custom.proto";
 import "dcs/group/v0/group.proto";
 import "dcs/hook/v0/hook.proto";
+import "dcs/metadata/v0/metadata.proto";
 import "dcs/mission/v0/mission.proto";
 import "dcs/net/v0/net.proto";
 import "dcs/srs/v0/srs.proto";

protos/dcs/metadata/v0/metadata.proto

@@ -0,0 +1,26 @@
+syntax = "proto3";
+package dcs.metadata.v0;
+option csharp_namespace = "RurouniJones.Dcs.Grpc.V0.Metadata";
+option go_package = "github.com/DCS-gRPC/go-bindings/dcs/v0/metadata";
+
+//A service to get administrative/meta data like server health checks and version
+service MetadataService {
+
+  rpc GetHealth(GetHealthRequest) returns (GetHealthResponse) {}
+
+  rpc GetVersion(GetVersionRequest) returns (GetVersionResponse) {}
+}
+
+message GetHealthRequest {
+}
+
+message GetHealthResponse {
+  bool alive = 1;
+}
+
+message GetVersionRequest {
+}
+
+message GetVersionResponse {
+  string version = 1;
+}

src/rpc.rs

@@ -16,6 +16,7 @@ mod controller;
 mod custom;
 mod group;
 mod hook;
+mod metadata;
 mod mission;
 mod net;
 mod srs;

src/rpc/metadata.rs

@@ -0,0 +1,26 @@
+use stubs::metadata::v0::metadata_service_server::MetadataService;
+use stubs::*;
+use tonic::async_trait;
+use tonic::{Request, Response, Status};
+
+use super::MissionRpc;
+
+#[async_trait]
+impl MetadataService for MissionRpc {
+    async fn get_health(
+        &self,
+        _request: Request<metadata::v0::GetHealthRequest>,
+    ) -> Result<Response<metadata::v0::GetHealthResponse>, Status> {
+        let alive: bool = true;
+        return Ok(Response::new(metadata::v0::GetHealthResponse { alive }));
+    }
+
+    async fn get_version(
+        &self,
+        _request: Request<metadata::v0::GetVersionRequest>,
+    ) -> Result<Response<metadata::v0::GetVersionResponse>, Status> {
+        const VERSION: Option<&str> = option_env!("CARGO_PKG_VERSION");
+        let version = VERSION.unwrap_or("unknown").to_string();
+        return Ok(Response::new(metadata::v0::GetVersionResponse { version }));
+    }
+}

src/server.rs

@@ -17,6 +17,7 @@ use stubs::controller::v0::controller_service_server::ControllerServiceServer;
 use stubs::custom::v0::custom_service_server::CustomServiceServer;
 use stubs::group::v0::group_service_server::GroupServiceServer;
 use stubs::hook::v0::hook_service_server::HookServiceServer;
+use stubs::metadata::v0::metadata_service_server::MetadataServiceServer;
 use stubs::mission::v0::mission_service_server::MissionServiceServer;
 use stubs::mission::v0::StreamEventsResponse;
 use stubs::net::v0::net_service_server::NetServiceServer;
@@ -209,7 +210,7 @@ async fn try_run(
         auth_config,
     } = state;
 
-    let mut mission_rpc =
+    let mut mission_rpc: MissionRpc =
         MissionRpc::new(ipc_mission.clone(), stats.clone(), shutdown_signal.clone());
     let mut hook_rpc = HookRpc::new(ipc_hook, stats, shutdown_signal.clone());
 
@@ -260,6 +261,7 @@ async fn try_run(
         .add_service(CustomServiceServer::new(mission_rpc.clone()))
         .add_service(GroupServiceServer::new(mission_rpc.clone()))
         .add_service(HookServiceServer::new(hook_rpc))
+        .add_service(MetadataServiceServer::new(mission_rpc.clone()))
         .add_service(MissionServiceServer::new(mission_rpc.clone()))
         .add_service(NetServiceServer::new(mission_rpc.clone()))
         .add_service(TimerServiceServer::new(mission_rpc.clone()))

stubs/src/lib.rs

@@ -10,6 +10,7 @@ pub mod controller;
 pub mod custom;
 pub mod group;
 pub mod hook;
+pub mod metadata;
 pub mod mission;
 pub mod net;
 pub mod srs;

stubs/src/metadata.rs

@@ -0,0 +1,3 @@
+pub mod v0 {
+    tonic::include_proto!("dcs.metadata.v0");
+}